In recent years, it has been strongly required to convert hand-written characters, pictures, symbols, etc., into electronic data capable of being treated by an information processing apparatus. In particular, there is an increasing demand for a system capable of inputting hand-written information data into computers, etc., at a real time without using any reading device such as a scanner.
To meet the above demands, there have been proposed, for example, write-type input devices including an input unit equipped with a pen and a writing plane for inputting data by hand-writing, an input locus reading unit for reading an input locus upon inputting the data by hand-writing using the input unit, an input locus conversion unit for converting the input locus information into electronic data, and an input locus data transmission unit for transmitting the electron data obtained by the input locus conversion unit to an information processing apparatus. In the above input devices, the input locus reading unit is capable of reading marks for providing a position information which are formed on the writing plane, by a sensor fitted to the pen. The writing plane is constituted from a special paper on which specific dot patterns capable of absorbing an infrared ray are printed as the marks for providing the position information, whereas the pen is provided with an infrared irradiation portion for irradiating an infrared ray to the writing plane, and an infrared sensor for detecting infrared patterns reflected from the dot patterns.
Also, there have been proposed write-type input devices of such a type which includes a writing panel and a pressure-sensitive sensor, an electrostatic sensor or an optical sensor disposed in the writing panel, and is capable of attaining an input locus by detecting a writing pressure, a static electricity or a shade when hand-writing input data on a surface of the writing panel using a stylus-type pen or fingers.
However, in the former input devices, although the hand-written contents (input locus) are converted into the electronic data, since the special paper is exclusively used as a direct inputting means, a separate display device is required to display the input locus information converted into the electronic data. Further, although the locus information is visually recognized by using the pen fitted with graphite or ink for recording the locus on the paper, the input devices are unsuitable for use in intuitive and interactive applications such as hand-writing input, for example, on a diagram or graph displayed on a display device, and also require a wider working space upon inputting. In addition, since the paper on which the locus is once recorded and inputted by hand-writing is not reusable, it is required to always reserve the inputting papers as expendable items. Therefore, the input devices are unsuitable, in particular, in mobile applications.
On the other hand, in the latter input devices including the writing panel and the pressure-sensitive sensor or electrostatic sensor disposed therein, reduction in size thereof is more difficult as compared to the former input devices, resulting in increase in weight and thickness of the devices as well as high production costs. In addition, the pressure-sensitive sensor or electrostatic sensor tends to suffer from errors when contacted with hands and cuffs. Therefore, the input devices are unsuitable for such ordinary writing procedures as used for writing on note books, etc., which are performed while contacting a side face of the little finger of a writer therewith. The input devices might be usable in intuitive and interactive applications such as hand-writing input, for example, on a diagram or graph displayed on a display device by fitting a writing panel made of a transparent material onto a front face of the display device or imparting a displaying function to the writing panel itself. However, in the input devices of this type, it is difficult to increase a size of an image screen of the display device owing to expensiveness thereof and reduce a size and weight of the devices. Therefore, the input devices are unsuitable for use in mobile applications such as cellular phones.
To solve these problems, there is a demand for input devices capable of inputting contents directly hand-written on an image screen of a display device into an information processing apparatus, which are compact in size and producible with low costs. To meet such a demand, for example, in the former write-type input devices, the paper having the printed dot pattern as the writing means which exhibits a transparency to a light in a visible range may be disposed on or ahead of a front face of the display device.
As the sheet satisfying these requirements, for example, JP 2003-256137A discloses the transparent sheet to be disposed on or ahead of a front face of a display device in which marks for providing a position information indicating a position of an input locus inputted by an electronic pen, etc., are printed with an ink capable of emitting a light readable by the input locus reading device when irradiating a light having a predetermined wavelength thereto. However, JP 2003-256137A fails to specify the kind of ink capable of realizing such a transparent sheet, etc., and therefore it is considered that JP 2003-256137A describes only an idea or a desire or wish for the transparent sheet without illustrating specific transparent sheets.
Further, JP 2001-243006A discloses a coordinate input device using a transparent member printed with a specific ink capable of reflecting a light in an infrared range. However, JP 2001-243006A also fails to specify the kind of ink capable of realizing such an input device, etc., and therefore it is considered that JP 2001-243006A describes only an idea or a desire or wish for the input device without illustrating specific transparent sheets.